Portable griddle stove with dual cooking surfaces

ABSTRACT

A portable griddle stove has two non-stick cooking surfaces, either of which can withstand being on the underside of the cooking surface in use and the heat applied to the underside surface. A heat shield and heat diffuser control the temperature applied to the underside of the cooking surface by providing radiant heat to the center portion of the cooking surface and cooling the combustion gas diffused to the perimeter of the cooking surface. Secondary air provided through openings in case the and heat shield assist in cooling the combustion gas.

FIELD OF THE INVENTION

[0001] The present invention relates to a portable griddle stove, moreparticularly to a portable griddle stove with dual cooking surfaces.

BACKGROUND INFORMATION

[0002] Cooking devices used for camping and other outdoor activities arewell known in the art. For example, The Coleman Company, Inc. ofWichita, Kans. has been manufacturing portable cooking stoves for manyyears. Such portable cooking stoves include, for example, one or twoburners supplied with propane by an attachable tank. Such a portablestove provides direct flame impingement on the cooking surface placed onthe burner, generally a pot or skillet. Direct flame impingement doesnot present a problem in this circumstance as the pot or skillet isdesigned to withstand the heat from the flames. Even pots or skilletsthat include a non-stick coating on the cooking surface, such as TEFLON®manufactured by DuPont of Delaware, can be used with the portable stoveas the underside of the pot or skillet is untreated metal that canwithstand the direct flame impingement, whereas a non-stick surfacecould not withstand the high temperature from direct flame impingement.In addition, portable stoves generally do not provide a cooking surfaceand if a cooking surface is provided, the cooking surface is oftentreated with a non-stick coating and thus cannot be reversible as theunderside would then have a non-stick coating that would be damaged fromthe heat.

[0003] Another type of portable cooking device is a barbecue grill,whether fueled by charcoal, natural gas or propane. While a barbecue isoften portable, it is not suitable for use indoors due to safety reasonsand size limitations. Further, the cooking surface for a barbecue grillis generally a metal grill that provides sufficient support for the foodto be cooked while allowing the heat from the charcoal or burners topass directly through the grill to cook the food. Barbecue grillsgenerally do not provide a solid cooking surface such as griddlesurface.

[0004] There do exist reversible cooking surfaces, such as a cast irongriddle manufactured by the Lodge Manufacturing Company that provides acast iron plate that can be placed over a heat source such as flamesfrom a campfire, either side of the cast iron plate providing a cookingsurface such as a flat surface on one side and a grooved surface onanother side. Such a plate, however, cannot have a non-stick coating onboth sides of the griddle that would be exposed to high temperatures.

[0005] A popular cooking surface that is not suitable for portable oroutdoor use is an electric griddle. An electric griddle usually includesa non-stick cooking surface that is heated on its underside by anelectrically heated coil. Such an electric griddle requires a source ofalternating current electrical power that is often not available forconvenient portable or outdoor use, such as when camping or hiking.

[0006] Thus, it is desirable to have a portable cooking system thatprovides two non-stick cooking surfaces.

SUMMARY OF THE INVENTION

[0007] A portable cooking system includes a tube burner and a diffuserdisposed above the tube burner providing radiant heat to the centerportion of the cooking surface and directing combustion gas towards theperimeter of the cooking surface. A secondary air flow system providessecondary air to mix with the diffused combustion gas to control thetemperature of the combustion gas impinging on the perimeter of thecooking surface. As a result of the diffuser and the secondary air flowsystem, the temperature of the heat applied to the underside of thecooking surface in use can be controlled to allow the underside surfaceto have a non-stick coating.

BRIEF DESCRIPTION OF THE DRAWING

[0008]FIG. 1 illustrates an exploded view of an exemplary griddle stoveaccording to an embodiment of the present invention.

[0009]FIGS. 2A and 2B illustrate exemplary cooking surfaces according toan embodiment of the present invention.

[0010]FIG. 3 illustrates an exemplary connection of a venturi assemblyaccording to an embodiment of the present invention.

[0011]FIG. 4 illustrates an exemplary ignition system according to anembodiment of the present invention.

[0012]FIG. 5 illustrates an exemplary regulator assembly connectoraccording to an embodiment of the present invention.

[0013]FIG. 6 illustrates an exemplary heat shield assembly according toan embodiment of the present invention.

[0014]FIG. 7 illustrates an exemplary case according to an embodiment ofthe present invention.

[0015]FIG. 8 illustrates an exemplary opening in a cooking surfaceaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016] As illustrated in FIG. 1, a griddle stove according to anexemplary embodiment of the present invention includes, for example, achassis, a fuel delivery system, an electronic ignition system, a heatdistribution system and cooking surfaces. The chassis includes, forexample, a case 6, leg brackets 3, 4 and handles 7. Handles 7 have, forexample, universal design so that a particular handle 7 can be used oneither end of the griddle. The particular appearance and structure ofhandles are a matter of design choice provided that adequate support isprovided for the case 6 and other components of the grill. The legbrackets 3, 4 and handles 7 are formed of, for example, glass fillednylon, such as polyester thermoplastic, flame retardant, 30% glass whichhas high heat properties and moderate cost, although other suitablematerial could be used. The leg brackets 3, 4 provide exemplary means toconnect the handles 7 to case 6 and also provide stiffness to the case 6as well as thermal isolation between the case 6 and the handles 7. Case6 is formed of, for example, cold rolled steel, draw quality, and can bepainted with heat-resistant paint if desired. The chassis also providesstructural support for the other components of the griddle as describedbelow.

[0017]FIGS. 2A and 2B illustrate two exemplary cooking surfaces 21, 22disposed on opposite sides of griddle 10. Griddle 10 is formed of, forexample, cast aluminum having a nonstick surface coating, such asTEFLON, on cooking surfaces 21 and 22. Griddle 10 can attach to case 6by, for example, a slip fit or other suitable connection means.

[0018] Cooking surface 21 includes a series of raised ribs extendingsubstantially the length of cooking surface 21 while cooking surface 22includes a flat cooking area 24 and a series of shorter raised ribsdisposed at an end area of the cooking surface. The configuration of thecooking surfaces 21, 22 are merely illustrative as any desired patterncan be provided on a particular cooking surface. By having two cookingsurfaces 21, 22, the need to carry additional cooking supplies whencamping, such as a griddle for pancakes and a grill or fish or meat, isminimized.

[0019] According to an exemplary embodiment of the present invention,griddle 10 includes a roughly circular opening 25. Because griddle 10 inan embodiment of the present invention includes two cooking surfaces 21,22, both cooking surfaces 21, 22 can generate grease when in use, suchas from frying bacon. Accordingly, the grease has to be withdrawn fromthe cooking surface to avoid spillage and undesired flare-up as well asdrawing the grease away from the food being cooked. It is preferable forthe grease to drip directly downward into drip tray 1 which is removablyattachable to handle 7. Opening 25 is provided in cooking surfaces 21,22 for waste removal.

[0020] As shown in FIG. 1, drip tray 1 connects to handle 7 and extendsunder the cooking surface 21, 22 (dimple). The connection between driptray 1 and handle 7 can be via, for example, tabs on drip tray 1 thatlock into corresponding holes in handle 7. Drip tray 1 is made of, forexample, the same material as handle 7. To achieve the desired flow ofwaste through opening 25 and into drip tray 1, a series of bumps 26 orother suitable protrusions are disposed, for example, around theperimeter of opening 25 which induce the waste flowing through theopening 25 to form drops and fall directly into drip tray 1 instead ofrunning along the undersurface of griddle 10. The bumps or protrusions26 provide a specific path for the liquid to follow through opening 25.

[0021] According to an exemplary embodiment of the present invention,not only can two different cooking surfaces be provided on a singlegriddle 10, but also each cooking surface can have a non-stick coatingthat is not damaged when the cooking surface not in use is exposed toheat from the heat distribution system. As illustrated in FIG. 1, theheat distribution system includes, for example, heat shield 13, tubeburner 15 and heat diffuser 11.

[0022] Tube burner 15 is conventional as is known in the art andincludes a plurality of openings along two sides to emit the air-fuelmixture to be ignited upon emission from the openings of tube burner 15.Tube burner 15 may be made of aluminized steel or other suitablematerial. Heat shield 13 is disposed below tube burner 15 and connectedto case 6 for support. Heat shield 13 minimizes heat transfer to thecase 6 by acting as a radiant shield, thereby allowing safe tabletoptemperatures with a low profile. Heat shield 13 can be manufactured of,for example, aluminized steel and could also be aluminum, stainlesssteel or a plated steel. The heat shield 13 channels secondary air totube burner 15 as described below.

[0023] Heat diffuser 11 acts as a barrier between the tube burner 15 andthe undersurface of the griddle 10 (e.g., the cooking surface 21, 22 notin use). The heat diffuser 11 prevents, for example, flames from thetube burner 15 from impinging directly on the non-stick coating on theundersurface of the griddle 10 and spreads the combustion gases towardsthe perimeter of the griddle 10. Heat diffuser 11 can be made of, forexample, stainless steel, such as 430 stainless steel due to the desireto have the diffuser resist corrosion and withstand high temperatures,although cold rolled steel also could be used but may present corrosionproblems.

[0024] As illustrated in FIG. 1, heat diffuser 11 has side portions 112that extend upwards towards griddle 10 and angle towards the perimeterof griddle 10. In addition, the projections 110 on the diffuser 11 areconfigured to form openings 111 between adjacent projections 110 thathave a quasi V-shape. For example, the openings 111 could have anapproximately 8 degree opening.

[0025] In operation, combustion gas (e.g., propane ignited upon exitfrom the tube burner 15) provides a flame that naturally flows upwardstowards the side portions 112 of heat diffuser 11. By angling sideportions 112 upwards, the side portions 112 are optimally positioned toreceive maximum heating from the flames. The flames from tube burner 15heat the side portions 112 of diffuser 11 which in turn provides radiantheat towards the center portion of griddle 10. Thus, there is little, ifany, direct flame impingement on the center of griddle 10, the use ofradiant heat from diffuser 11 protecting the non-stick coating on theundersurface of griddle 10.

[0026] Since the heat generated by the combustion gas is greatest at thecenter portion of the griddle 10 and decreases towards the perimeter ofthe griddle, the projections 110 of diffuser 11 push the combustion gasaway from the center of the griddle 10. Openings 111 between projections110 allow some combustion gas to escape towards the undersurface ofgriddle 10 for heating purposes while the projections 110 push thecombustion gas further towards the perimeter of the griddle 10 toachieve even heating of the entire cooking surface 21, 22 instead ofconcentrating the heating in the center portion of the griddle 10.

[0027] Even with the projections 110 pushing the combustion gas towardsthe perimeter of the griddle 10, the combustion gas may not besufficiently cooled and could damage the nonstick coating on theundersurface of the griddle 10. Accordingly, in an exemplary embodimentof the present invention, a secondary air system is utilized. Referringto FIG. 6, heat shield 13 includes, for example, a center portion 132and two edge portions 131, 133 extending from either side of centerportion 132 and angled upwards so as to be angled towards burner tube 15(e.g., see FIG. 1). Center portion 132 includes, for example, a seriesof openings 134 disposed below tube burner 15. Openings 134 channelsecondary air to the tube burner 15. Some additional air may beavailable from a gap between the undersurface of griddle 10 and upperportion of case 6 adjacent to the handle. With no additional airflow tomix with the combustion gas, however, the combustion gas could besufficiently hot to damage the underside of the non-stick cookingsurface as well as the bottom pan of the grill (e.g., a painted surfaceon the bottom of case 6 could burn).

[0028] Accordingly, a secondary air system is utilized according to anexemplary embodiment of the present invention. Edge portions 131, 133 ofheat shield 13 include, for example, openings 135 that provideadditional air flow to cool the combustion gas that is pushed to theperimeter of the griddle 10 by the heat diffuser 11. Openings 135 arearranged to create a flow of air between openings 135 and openings 60 inthe bottom of case 6, as illustrated in FIG. 7. For example, openings134 and 135 in heat shield 13 are arranged offset from openings 60 incase 6 to provide an airflow path. Openings 134 and 135 are generallynot aligned with openings 60 to prevent a direct path for heat radiationto the tabletop or other surface on which the stove is placed. Alignmentof openings could generate a hotspot on the underlying surface andcreate a safety problem.

[0029] Accordingly, openings 60 in case 6 and openings 134, 135 in heatshield 13 allow fresh air into the grill and can be arranged as afunction of offset placement of the openings to channel fresh air topredetermined locations so, for example, the fresh air interacts withthe combustion gas towards the perimeter of the diffuser 11. It isfurther noted that by angling the edge portions 131, 133 of heat shield13 towards tube burner 13 and the perimeter of griddle 10, the mixing ofthe secondary air with the combustion gas not only cools the combustiongas to a safe temperature for interaction with the underside of thecooking surface, but also causes the volume of combustion gas to expand,thus causing the combustion gas to expand above the heat diffuser 11 tosafely heat the perimeter of the cooking surface 21, 22. The combinationof the heat diffuser 11 and heat shield 13 also dilutes the combustiongases to cool and disperse the heat generated by tube burner 15 so as tonot harm the underside cooking surface 21, 22 and provide even heatingof the griddle 10.

[0030] The fuel delivery system includes, for example, a conventionalregulator assembly 14 that connects to a propane tank (not shown), and aventuri assembly 12 connected to a tube burner 15. Fuel is provided, forexample, by a propane tank (not shown) attached to the regulatorassembly 14, such as a portable propane tank manufactured by The ColemanCompany, Inc. of Wichita, Kans. According to an exemplary embodiment ofthe present invention, the regulator assembly 14 connects to the venturiassembly 12 via, for example, spring clip 36. In this case, no clockingof the regulator assembly 14 or threading is required compared to aconventional connection which employs a threaded connection or notch andlock mating between the regulator and the burner tube 15 via the venturiassembly 12.

[0031] As illustrated in FIGS. 3 and 5, according to an exemplaryembodiment of the present invention, venturi assembly 12 is generallycylindrical with a tube mating portion 30 that attaches to the tubeburner 15 via, for example, a slip fit. An alternative connection couldbe, for example, a press fit or threaded connection. Adjacent to tubemating portion 30 is a center portion 31 including openings 32. Openings32 allow air to mix with the fuel that passes through center portion 31.Towards one end of center portion 31, a groove 33 extends around thecircumference of the center portion 31. Along a portion of thecircumference of groove 33, for example 90° of the circumference ofgroove 33, material is completely removed (e.g., a slot is milled) sothat an opening extends around a portion of the circumference of centerportion 31. Accordingly, groove 33 can releasably receive a spring clip36 having a flat portion 37 and cylindrical portion 38, the flat portion37 being disposed in the opening in groove 33. Flange 34 bears againstthe backside of cover 8 to prevent venturi assembly 12 from slipping outof tube burner 15. End portion 35 protrudes through cover 8 to providethe point of connection for connector 50 of regulator assembly 14.

[0032] As shown in FIG. 5, connector 50 of regulator assembly 14includes, for example, hexagonal portion 51 providing a threadedconnection to a connector tube of regulator assembly 14 transportingfuel towards the venturi assembly 12. Adjacent to hexagonal portion 51is, for example, a cylindrical center portion 52. Groove 53 having, forexample, a profiled edge 53A, is disposed between center portion 52 andgastip 54 and extends the circumference of center portion 52. Gastip 54includes, for example, a profiled edge 54A. In an embodiment of thepresent invention, profiled edge 54A forms a lesser angle with respectto horizontal than profiled edge 53A.

[0033] Thus, in operation gastip 54 of connector 50 is inserted into endportion 35 of venturi assembly 12. When gastip 54 is inserted intoventuri assembly 12, profiled edge 54A engages spring clip 36, which isdisposed in groove 33, the flat portion 37 of spring clip 36 extendingthrough the opening in groove 33. With sufficient force applied toconnector 50, profiled edge 54A passes under spring clip 36 and flatportion 37 engages groove 53 in connector 50. As a result, regulatorassembly 14 is held in place in venturi assembly 12 by spring clip 36.To remove connector 50, force is applied to connector 50 to extract itfrom venturi assembly 12, the force required generally being greater forremoved than insertion due to the steeper edge 53A having to beovercome. According to an exemplary embodiment of the present inventionemploying such a spring clip connection or other similar connection,operation of the portable grill is simplified and the orientation of thefuel tank is no longer relevant. Connector 50 and venturi assembly 12can be made of, for example, brass or plated steel. It will beappreciated by those skilled in the art that the above describedconnection of venturi assembly 12 and connector 50 can be utilized forconnecting other components in a similar manner.

[0034] The ignition system according to an exemplary embodiment of thepresent invention is conventional as is known in the art. The ignitionsystem includes, for example, an ignition box 16, an electrode 17, apiezoelectric igniter 18 and a grounding strap 5 as illustrated in FIGS.1, 4 and 6. The electrode 17 attaches to the ignition box 16 with, forexample, a screw, forming a spark gap through which a portion of thefuel-air mixture flows. The piezoelectric igniter 18 attaches to thecover 8 with, for example, igniter bracket 9 and screws. The groundingstrap 5 attaches to the cover and provides grounding to the chassis.Button cover 2 may press into the cover to conceal the tip of thepiezoelectric igniter 18.

[0035] Thus, according to an exemplary embodiment of the presentinvention, a portable griddle stove is provided that has two non-stickcooking surfaces 21, 22, either of which can withstand being on theunderside of the cooking surface in use and the heat applied to theunderside surface. A heat shield 13 and heat diffuser 11 control thetemperature applied to the underside of the cooking surface by providingradiant heat to the center portion of the cooking surface 21, 22 andcooling the combustion gas diffused to the perimeter of the cookingsurface 21, 22. Secondary air provided through openings in case 6 andheat shield 13 assist in cooling the combustion gas.

What is claimed is:
 1. A stove, comprising: a housing; a heatdistribution system disposed in the housing; and a griddle removablyconnected to the housing; wherein the griddle includes a first sidehaving a first non-stick cooking surface and a second side opposite thefirst side, the second side having a second non-stick cooking surface,one of the first side and the second side being facing towards the heatdistribution system.
 2. The stove according to claim 1 , wherein theheat distribution system includes a heat shield connected to thehousing, a tube burner disposed above the heat shield and a heatdiffuser disposed above the tube burner.
 3. The stove according to claim2 , wherein the heat diffuser includes a center portion adjacent twoangled portions, each of the two angled portions having a plurality ofprojections, a plurality of openings being formed between adjacentprojections.
 4. The stove according to claim 1 , further comprising ahandle attached to each end of the housing, a drip tray being removablycoupled to the handle at one end of the housing.
 5. The stove accordingto claim 4 , wherein an opening extends through the first side andsecond side of the griddle, a plurality of protrusions being arrangedalong a perimeter of the opening, the opening being disposed above thedrip tray.
 6. The stove according to claim 1 , further comprisingventuri assembly connected to the heat distribution system and aregulator assembly connected to the venturi assembly.
 7. The stoveaccording to claim 6 , wherein the venturi assembly includes acylindrical portion having a circumferential groove, a portion of thecircumferential groove being removed to form a slot, a spring clip beingremovably disposed in the groove.
 8. The stove according to claim 7 ,wherein the regulator assembly includes a connector having a profilededge adjacent a circumferential groove, the connector releasablyengaging the cylindrical portion of the venturi assembly, the profilededge releasably engaging a flat portion of the spring clip disposed inthe slot, the flat portion of the clamp also being disposed in thecircumferential groove of the connector.
 9. The stove according to claim7 , wherein the spring clip includes a flat portion.
 10. A connectorassembly, comprising: a first mating portion including a cylindricalportion having a circumferential groove, a portion of thecircumferential groove being removed to form a slot, a spring clip beingremovably disposed in the groove; and a second mating portion having afirst profiled edge adjacent a circumferential groove, the second matingportion releasably engaging the cylindrical portion of the first matingportion, the first profiled edge releasably engaging a flat portion ofthe spring clip disposed in the slot, the flat portion of the clip alsobeing disposed in the circumferential groove of the second matingportion.
 11. The connector assembly according to claim 10 , furtherincluding a second profiled edge adjacent the circumferential groove ofthe second mating portion, the second profiled edge forming a greaterangle than the first profiled edge so as to inhibit disengagement of thefirst mating portion and the second mating portion.
 12. A heatdistribution system, comprising: a heat shield connected to a housing; aburner disposed above the heat shield; and a heat diffuser disposedabove the tube burner.
 13. The heat distribution system according toclaim 12 , wherein the heat diffuser includes a center portion adjacenttwo angled portions, a plurality of projections extending from each ofthe two angled portions, a plurality of openings being formed betweenadjacent projections.
 14. The heat distribution system according toclaim 13 , wherein the center portion is disposed at a level lower thana level of the plurality of projections.
 15. A griddle, comprising: asubstrate; a first cooking surface disposed on a first side of thesubstrate; and a second cooking surface disposed on a second side of thesubstrate opposite the first side, wherein each of the first cookingsurface and the second cooking surface include a non-stick surfacecoating.
 16. The griddle according to claim 15 , wherein the substrateis formed of one of cast iron and cast aluminum.
 17. The griddleaccording to claim 15 , wherein the first surface includes a pluralityof ribs extending substantially along a length of the first cookingsurface.
 18. The griddle according to claim 15 , wherein the secondcooking surface includes a plurality of ribs extending along a portionof the second cooking surface, a remainder of the second cooking surfacebeing substantially flat.
 19. The griddle according to claim 15 ,wherein a perimeter of the first cooking surface and the second cookingsurface include a raised edge.
 20. The griddle according to claim 15 ,wherein an opening is disposed through the first cooking surface, thesubstrate and the second cooking surface.
 21. The griddle according toclaim 20 , wherein a plurality of protrusions are formed along an inneredge of the opening.